The reading of all good books is like a conversation with the finest men of past centuries
René Descartes (1845-1898)

Damage to Book Covers

When we walk into a library for a book, we expect to find it in good condition with all the pages intact. A bookcover facilitates the use of the book and is essential for its preservation. It not only protects the pre-arranged order of the enclosed paper pages, but also protects against the deteriorating influences of dust, light, moist, insects, fungi, etc. Treatment of book covers and their covering, usually either paper, leather or parchment, demands special attention.
Books, whatever their age, continue to be used - some more, some less, as opposed to (other) museological artefacts. And it's especially the book cover that is put under strain during use.

Damages and dangers

Deterioration of the condition of leather and parchment can have several causes, and even relatively new materials can be affected. In most cases the cause of deterioration can be traced to production methods or environmental factors. A well-known and serious form of leather damage is "red rot", where the fibres break and eventually are reduced to powder. Another damage is caused by the use of corrosive materials for ornamentation. Frequently occurring causes of deterioration are dehydration of materials from the use of wrong leather dressings and storing conditions which are too arid. The intake of sulphur oxide (SO₂) from the environment, which eventually transforms into sulphuric acid, leads to acidification. In the production process of parchment durability is attained not through tanning as with leather but through a treatment with calcium, which has the important side effect of acting as a buffer against acidification. Therefore, apart from mechanical damage, parchment of book covers is often in better condition than leather coverings. Other dangers to leather and parchment are insects and fungi, although it must be stated that in most cases it is not the material itself but the glues or finishing coats which are used as substrate.

Preservation solutions

Almost from the start of the use of book covers as we know them there has been the tendency of treating the covers with one substance or another to make them look `better', to make them `shine'. This, of course, next to the more legitimate treatments with a view to preservation. The range of materials which have been used towards these goals over the past few centuries is nothing less than amazing. At first we see materials which were already in use in the household: mainly soaps but also turpentine, gasoline, eau de cologne and even skimmed milk have been applied for preservation and embellishment. In the 19th century "Propert's Leather and Saddle Soap" was highly recommended for `the scrubbing of leather book covers'. Leather that is regularly treated with soaps gets highly alkaline, with darkened and broken grains. The use of soaps causes deeper penetration and clogging of the grains with dirt, soaps and fats. In the English magazine "The Housekeeper's Week" one author in 1908 recommends cleaning of book covers by the use of rubblestone powder, applied with a cotton cloth. Undoubtedly the covers not only were clean after this treatment, but also worn - and very much so! In the 20th century restaurators gradually became aware of the dangers of the use of `household' materials and changed to well-founded treatments of leather and parchment book covers and the storage of book materials in general.